Biostatistical expertise was provided to researchers from NCI and other institutions on the design and statistical analysis of a broad range of laboratory studies including: host cell reactivation studies in the Dermatology Branch, NCI, to examine blockage of transcription due to defective nucleotide excision repair of specific lesions induced by oxygen radicals in cells from patients with xeroderma pigmentosum and Alzheimer's disease; development of an assay to measure the repair of a single DNA lesion placed in a specific location in a plasmid; studies of survival of knockout mice with the Veterinary and Tumor Pathology Section, Animal Sciences Branch, NCI; experiments in the Molecular Genetics Section of the Laboratory of Molecular Biology, NCI, examining mutation rates in transgenic mice and wild type mice, and comparing melanoma incidence rates in different strains of transgenic mice; a study of methylation and Ras mutations in skin cancers induced in mice by initiation with DMBA and promotion with TPA or mezerein in the Laboratory of Cellular Carcinogenesis and Tumor Promotion, NCI; a study of retinal content in the liver of transgenic mice in the Laboratory of Cellular Carcinogenesis and Tumor Promotion, NCI; an investigation in the Laboratory of Molecular Genetics of the NIA evaluating mutational spectra and microsatellite instability in immunoglobulin genes in order to explore mechanisms for hypermutation; a study by the Laboratory of Molecular Genetics of the NIA measuring repair of oxidative DNA damage in brain tissue from patients with primary neurologic degenerations; a study of the effects of UV exposure on the size of p53-mutant clones in the skin of knockout mice with the Yale University Department of Therapeutic Radiology and Genetics; a study by the University of Minnesota Laboratory of Environmental Medicine and Pathology of chromosome damage and hormone levels in pesticide appliers.